The effect of water pollution on biodiversity and abundance of aquatic invertebrates : a study in southern Sweden

Föroreningar i landskapets vatten kan spridas genom många olika faktorer, exempelvis via reningsverk, skogsbruk och jordbruk. De organismer som lever i vattenmiljöer kan vara mycket känsliga för de föroreningar som släpps ut, vilket kan leda till allvarliga konsekvenser som förlust av biologisk mångfald och andra förändringar inom dessa samhällen. Akvatiska evertebrater utgör bra bioindikatorer för vattenföroreningar då viss taxa är känsligare mot föroreningar än andra. I denna studie har akvatiska evertebrater samlats in från områden vid fem olika reningsverk i södra Sverige under sommar och höst. Syftet med studien är att undersöka hur vattenföroreningar som är orsakade av mänsklig aktivitet påverkar den biologiska mångfalden och abundansen. Det samlades in prover uppströms och nedströms med reningsverket, samt vid utlopp. Prover samlades in genom antingen kick-net eller specialgjorda fällor. Studien undersöker även om det finns en skillnad mellan de två olika insamlingsmetoderna som använts. Studien visade ingen signifikant skillnad när det kommer till abundans och biologisk mångfald gällande plats. Dock observerades en viss skillnad mellan platserna där det var högst biodiversitet och abundans uppströms. Resultatet visade även att det finns en signifikant skillnad i insamlingsmetod av akvatiska evertebrater där metoden med specialgjorda fällor visar på en högre abundans och biodiversitet av akvatiska evertebrater i jämförelse med metoden där kick-net användes. För framtida studier krävs mer data och ytterligare forskning för att studera hur vattenföroreningar påverkar biologisk mångfald och abundans på en mer detaljerad nivå.Wastewater treatment plants (wwtp), forestry and agriculture are some examples of how contaminants can spread in the landscape and cause water pollution. Organisms that live in water can be very sensitive to water pollution which could lead to several negative consequences, such as loss in biodiversity and other changes in these communities. Aquatic invertebrates are often used as bioindicators for pollutions since some orders of aquatic invertebrates are more sensitive towards contaminants than others. In this study, samples of aquatic invertebrates have been collected from areas of five different wwtp in southern Sweden during summer and fall. Furthermore, samples were taken upstream, downstream and at outfall at each wwtp. They were collected using either a kick-net method or a special trap. The purpose of this study is to investigate how water pollution affects aquatic invertebrates when it comes to biodiversity and abundance, and if there is a difference between the two different methods when collecting the samples. The study found no significant difference in biodiversity or abundance among the different locations. However, the study found a significant difference between the different sampling methods. The special traps indicated both higher abundance and higher biodiversity. For future studies, more data and more research are required to study water pollution and its effect on biodiversity and abundance on a more species specific and detailed level

Insights into bear evolution from a Pleistocene polar bear genome

The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental perturbations. In recent years, genomic studies have examined bear speciation and population history, including evidence for ancient admixture between polar bears and brown bears (Ursus arctos). Here, we extend our earlier studies of a 130,000- to 115,000-y-old polar bear from the Svalbard Archipelago using a 10x coverage genome sequence and 10 new genomes of polar and brown bears from contemporary zones of overlap in northern Alaska. We demonstrate a dramatic decline in effective population size for this ancient polar bear's lineage, followed by a modest increase just before its demise. A slightly higher genetic diversity in the ancient polar bear suggests a severe genetic erosion over a prolonged bottleneck in modern polar bears. Statistical fitting of data to alternative admixture graph scenarios favors at least one ancient introgression event from brown bears into the ancestor of polar bears, possibly dating back over 150,000 y. Gene flow was likely bidirectional, but allelic transfer from brown into polar bear is the strongest detected signal, which contrasts with other published work. These findings may have implications for our understanding of climate change impacts: Polar bears, a specialist Arctic lineage, may not only have undergone severe genetic bottlenecks but also been the recipient of generalist, boreal genetic variants from brown bears during critical phases of Northern Hemisphere glacial oscillations.Peer reviewe

Marine mammal hotspots across the circumpolar Arctic

Aim: Identify hotspots and areas of high species richness for Arctic marine mammals. Location: Circumpolar Arctic. Methods: A total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phyloge-netic groups (nine pinnipeds, three cetaceans, all species) and areas with high spe-cies richness were identified for summer (Jun-Nov), winter (Dec-May) and the entire year. Seasonal habitat differences among species’ hotspots were investigated using Principal Component Analysis. Results: Hotspots and areas with high species richness occurred within the Arctic continental-shelf seas and within the marginal ice zone, particularly in the “Arctic gateways” of the north Atlantic and Pacific oceans. Summer hotspots were generally found further north than winter hotspots, but there were exceptions to this pattern, including bowhead whales in the Greenland-Barents Seas and species with coastal distributions in Svalbard, Norway and East Greenland. Areas with high species rich-ness generally overlapped high-density hotspots. Large regional and seasonal dif-ferences in habitat features of hotspots were found among species but also within species from different regions. Gap analysis (discrepancy between hotspots and IUCN ranges) identified species and regions where more research is required. Main conclusions: This study identified important areas (and habitat types) for Arctic marine mammals using available biotelemetry data. The results herein serve as a benchmark to measure future distributional shifts. Expanded monitoring and teleme-try studies are needed on Arctic species to understand the impacts of climate change and concomitant ecosystem changes (synergistic effects of multiple stressors). While efforts should be made to fill knowledge gaps, including regional gaps and more com-plete sex and age coverage, hotspots identified herein can inform management ef-forts to mitigate the impacts of human activities and ecological changes, including creation of protected areas

Data from: Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic

We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1–3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat

Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change

Polar bears (PBs) are superbly adapted to the extreme Arctic environment and have become emblematic of the threat to biodiversity from global climate change. Their divergence from the lower-latitude brown bear provides a textbook example of rapid evolution of distinct phenotypes. However, limited mitochondrial and nuclear DNA evidence conflicts in the timing of PB origin as well as placement of the species within versus sister to the brown bear lineage. We gathered extensive genomic sequence data from contemporary polar, brown, and American black bear samples, in addition to a 130,000- to 110,000-y old PB, to examine this problem from a genome-wide perspective. Nuclear DNA markers reflect a species tree consistent with expectation, showing polar and brown bears to be sister species. However, for the enigmatic brown bears native to Alaska's Alexander Archipelago, we estimate that not only their mitochondrial genome, but also 5–10% of their nuclear genome, is most closely related to PBs, indicating ancient admixture between the two species. Explicit admixture analyses are consistent with ancient splits among PBs, brown bears and black bears that were later followed by occasional admixture. We also provide paleodemographic estimates that suggest bear evolution has tracked key climate events, and that PB in particular experienced a prolonged and dramatic decline in its effective population size during the last ca. 500,000 years. We demonstrate that brown bears and PBs have had sufficiently independent evolutionary histories over the last 4–5 million years to leave imprints in the PB nuclear genome that likely are associated with ecological adaptation to the Arctic environment.Published versio